Technical Field
The disclosed embodiments relate to the field of wireless communications, including multiuser block acknowledgment in wireless communications.
Background
A wireless communication protocol may be a contention-based protocol. For example, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 set of wireless communication protocols are contention-based protocols. A contention-based protocol allows many stations (e.g., users) to use the same channel without pre-coordination. In a contention-based protocol, a station checks that no other station is using the channel. If another station is using the channel, the station waits until the channel is free.
A contention-based wireless communication protocol may perform block acknowledgment. In block acknowledgement, an access point (AP) requests an acknowledgement of one or more frames from a station. Specifically, the AP sends a block acknowledgement request (BAR) frame to the station. In response, the station sends a block acknowledgement (BA) frame to the AP that acknowledges whether the one or more frames were successfully received. Because multiple frames can be acknowledged in a single BA frame, block acknowledgment often improves reliability and media access control (MAC) efficiency for a wireless communication protocol.
However, because a station may need to wait to access the channel in a contention-based wireless communication protocol, the station may be slow to send a BA frame to the AP. This increases power usage because the station repeatedly polls the channel to check that no other station is using it. This also decreases the data transmission rate and increases latency. Finally, there may be increased network congestion because multiple stations are forced to send BA frames one after the other to the AP.
A contention-based wireless communication may allow multiple BA frames to be included in a single frame. For example, a proposal for the IEEE 802.11ax standard allows multiple BA frames to be included in a single multiuser physical layer convergence physical layer protocol data unit (MU-PPDU). Specifically, a multi-station block acknowledgment (M-BA) frame enables an access point to send multiple BA frames in one downlink (DL) frame in response to an uplink (UL) frame, e.g., an UL MU-PPDU frame.